Emission Characteristic of NOx in CFB Boiler at Low Load

Abstract

In order to study the NOx emission of CFB boiler at low load, a bubbling fluidized bed test was established to investigate the effects of bed temperature, excess air ratio and particle size of ZY coal on NOx emission. A continuous feeder was used to ensure the feeding rate steady, so that the significant parameter excess air ratio can be confirmed. By comparing the NOx emissions of different conditions, the influence law of three parameters can be obtained. The results showed that the bed temperature had a continuous promoting effect on the formation of NOx when bed temperature increased from 700 to 850 °C. At a given temperature, the NOx emission depended mainly on the excess air ratio. With the increasing of excess air ratio, the NOx emission increased first and then decreased. In the same condition, the NOx emission generated in the combustion process of larger particle coal was lower than the value of small particle coal.